I've searched the forums but can't find my specific problem:
On my '68 280SL, the knurled knob on the back of the FIP (for adjusting idle mixture) seems stuck. I've adjusted it several times in the past with no problem, but now it will neither push in (to engage the internal slot) nor pull out. I can easily turn it (both CW and CCW) for about 1 1/2 turns end-to-end before it tightens in either direction, but with no detectable "clicks". Also, with the engine running, the knob is turning. So it seems to me that something inside the FIP has slipped and the knob is now always engaged. Before I start messing with the FIP, can anyone offer suggestions? I also recently detected a coolant leak that seems to come from somewhere near the rear of the engine. Could this be a related problem?
Thanks!